Circuit Description
WARNING: This page is about a different car, the 2003 GMC Sonoma and 2003 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.
The PCM enables the fuel pump relay when the ignition switch is turned on. The PCM will disable the fuel pump relay within 2 seconds unless the control module detects ignition reference pulses. PCM continues to enable fuel pump relay as long as ignition reference pulses are detected. PCM disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and ignition remains on.